During a hostage standoff in Cicero two years ago, authorities say, Nathaniel Beler had forced his two children into an apartment bathtub filled with enough gasoline to level the building.

The children were taken away from Beler and placed under the care of an agency that contracts with the state, according to a lawsuit filed this week, but were nevertheless left at a house with him three months later. Once again, the suit says, he soaked them in gasoline and this time lit a match.

Beler, his 3-year-old daughter Nariyah and the children's mother died in the subsequent fire. Beler's 9-year-old son, Naciere, survived with burns on almost half his body.

The wrongful-death lawsuit filed by Cook County Public Guardian Robert Harris alleges that the girl's death and her brother's injuries were the result of negligence and many missteps on the part of the agency, Association House of Chicago.

Only three weeks before the fatal fire, according to the lawsuit, a judge had criticized Association House for its poor handling of the family's case.

The lawsuit also alleges Association House failed to properly support the children's aunt, who had been appointed as their caregiver, to secure social work services for the family and to make sure Beler was getting the mental help he was ordered to receive after the incident two years ago.

"If Association House had monitored the children and serviced the family as required, it would have prevented Nariyah's death and Naciere's painful injuries and lifelong recovery," the suit states.

The children were placed in the agency's care in September 2012, just days after the first incident, according to the suit. On the day of the incident, their mother had left the house to go to work, even after he had threatened to kill them, but she later called police at the prompting of her co-workers, according to the suit.

"After rescuing the children, police officers discovered that the children's socks were soaked in gasoline from being forced into the bathtub," according to the suit. Beler was committed to a psychiatric hospital and diagnosed with schizophrenia, depression, anxiety, PCP abuse and noncompliance with medications.

Three months later, on Dec. 29, Beler set himself, the two children and their mother on fire at his mother's house, where their aunt had dropped them off the night before and where Beler was living, according to the lawsuit.

The children's mother died at the scene and Beler died the next day. Nariyah was burned over 98 percent of her body and died three days later, according to the suit. Naciere, now age 11, is in state custody and still faces several surgeries as part of a long and painful recovery, according to the suit.

Among other alleged lapses, the lawsuit cited juvenile court testimony by an Association House caseworker who said that the family was not receiving any of its recommended social services, including psychiatric care for the children's mother and an educational program for Beler's daughter.

The caseworker also told the judge that she had neither secured Beler's mental health records nor verified whether he was taking required medication for schizophrenia, anxiety and depression.

Beler had been discharged from a mental health center after the first incident with only two weeks of medications and never followed up with his psychotherapist, according to the suit.

The agency knew he had a history of both not taking his medication and of violent behavior in such instances. The agency was supposed to refer Beler for psychotherapy, substance abuse and random urine screenings to make sure he was not taking drugs but it never did, according to the suit.

Within two weeks of the children's placement with their aunt, she reported to the agency that she was struggling to take care of the children, according to the suit. But their caseworker moved slowly to fill out a daycare application for Nariyah and did not determine who was watching the kids when the aunt went to school three mornings a week or worked, the suit states.

The children spent nights with other relatives, who were not aware of court visitation orders and often allowed their mother to visit them without proper supervision, according to the suit.

Association House also failed to refer the children's mother and Naciere for required psychotherapy, and did not check to see if the mother was still in a relationship with Beler, according to the suit.

Association House did not return requests for comment and a DCFS spokesperson said Tuesday the agency does not comment on pending litigation.